Open Access Nano Express

First-principles investigation on the segregation of Pd at LaFe1-x Pd x O3-y surfaces

Zhi-xue Tian1, Akifumi Uozumi2, Ikutaro Hamada3, Susumu Yanagisawa4, Hidetoshi Kizaki1, Kouji Inagaki1 and Yoshitada Morikawa15*

Author affiliations

1 Division of Precision Science & Technology and Applied Physics, Graduate School of Engineering, Osaka University, 2-1, Yamada-okaSuita, Osaka 565-0871, Japan

2 Insitute of Scientific and Industrial Research, Osaka University, 8-1 MihogaokaIbaraki, Osaka 567-0047, Japan

3 Advanced Institute for Materials Research (AIMR), Tohoku University, Sendai 980-8577, Japan

4 Department of Physics and Earth Science, Faculty of Science, University of the Ryukyus, 1 SenbaruNishihara, Okinawa 903-0213, Japan

5 Elements Strategy Initiative for Catalysts and Batteries (ESICB), Kyoto University, Katsura, Kyoto 615-8520, Japan

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Citation and License

Nanoscale Research Letters 2013, 8:203  doi:10.1186/1556-276X-8-203

Published: 1 May 2013

Abstract

First-principles calculations were performed to investigate the effect of Pd concentration and oxygen vacancies on the stability of Pd at LaFeO3 surfaces. We found a much stronger tendency of Pd to segregate by taking the aggregation of Pd at LaFe1-xPdxO3-y surfaces into consideration, resulting in a pair of Pd-Pd around a vacancy. Moreover, we predicted that one oxygen-vacancy-containing FeO2-terminated surfaces would be stable at high temperatures by comparing the stability of LaFe1-xPdxO3-y surfaces, which further supports our previous conclusion that a Pd-containing perovskite catalyst should be calcined at 1,073 K or higher temperatures in air to enhance the segregation of Pd in the vicinity of surfaces to rapidly transform the Pd catalyst from oxidized to reduced states on the perovskite support.

Keywords:
Perovskite; LaFeO3; Palladium; Density functional theory; Surface segregation